github.com/cloudbase/juju-core@v0.0.0-20140504232958-a7271ac7912f/state/apiserver/common/ensuredead.go (about)

     1  // Copyright 2013 Canonical Ltd.
     2  // Licensed under the AGPLv3, see LICENCE file for details.
     3  
     4  package common
     5  
     6  import (
     7  	"launchpad.net/juju-core/state"
     8  	"launchpad.net/juju-core/state/api/params"
     9  )
    10  
    11  // DeadEnsurer implements a common EnsureDead method for use by
    12  // various facades.
    13  type DeadEnsurer struct {
    14  	st           state.EntityFinder
    15  	getCanModify GetAuthFunc
    16  }
    17  
    18  // NewDeadEnsurer returns a new DeadEnsurer. The GetAuthFunc will be
    19  // used on each invocation of EnsureDead to determine current
    20  // permissions.
    21  func NewDeadEnsurer(st state.EntityFinder, getCanModify GetAuthFunc) *DeadEnsurer {
    22  	return &DeadEnsurer{
    23  		st:           st,
    24  		getCanModify: getCanModify,
    25  	}
    26  }
    27  
    28  func (d *DeadEnsurer) ensureEntityDead(tag string) error {
    29  	entity0, err := d.st.FindEntity(tag)
    30  	if err != nil {
    31  		return err
    32  	}
    33  	entity, ok := entity0.(state.EnsureDeader)
    34  	if !ok {
    35  		return NotSupportedError(tag, "ensuring death")
    36  	}
    37  	return entity.EnsureDead()
    38  }
    39  
    40  // EnsureDead calls EnsureDead on each given entity from state. It
    41  // will fail if the entity is not present. If it's Alive, nothing will
    42  // happen (see state/EnsureDead() for units or machines).
    43  func (d *DeadEnsurer) EnsureDead(args params.Entities) (params.ErrorResults, error) {
    44  	result := params.ErrorResults{
    45  		Results: make([]params.ErrorResult, len(args.Entities)),
    46  	}
    47  	if len(args.Entities) == 0 {
    48  		return result, nil
    49  	}
    50  	canModify, err := d.getCanModify()
    51  	if err != nil {
    52  		return params.ErrorResults{}, err
    53  	}
    54  	for i, entity := range args.Entities {
    55  		err := ErrPerm
    56  		if canModify(entity.Tag) {
    57  			err = d.ensureEntityDead(entity.Tag)
    58  		}
    59  		result.Results[i].Error = ServerError(err)
    60  	}
    61  	return result, nil
    62  }